After an successfull prototype gamma stirling and some studying, My next project will be power producing engine for my house. I would be satisfied if it could produce some 5 KW of electrical power.

The heat source would be the fireplace. The engine would be built inside the chimney, so the smoke and hot air would warm the hot side. It would be water cooled with self-sustained cooling cycle (crank would spin a pump).

The preparatory engine design consists of four double-acting pistons. Each cylinder would have a hot and cold side separated by a piston, and the first cylinder's cold side would be connected to seccond ones hot side, seccond one's cold to third one's hot etc. so they would form a interconnected chain with 90 deg phase shift. I haven't yet thought of any crank mechanisms, maybe the engine wouldn't even need such mechanism, and thus the pistons could form a direct linear alternator.

I will, however, need help in terms of designing and machining tips. As it will be a power producing engine, It will have to withstand quite heavy loads on the mechanical parts. It would have to last for years without maintenance. Stainless steel is about only metal available that could render such a results, but I have no skill nor means of machining it.

Any ideas or thoughts?

They told me one cannot build a jet engine in garage conditions. I proved them wrong and I was only 16 :P